A--m-->B--->C = valid

• you can start at A, ride to B, and ride to C

A--->B--m-->C = invalid

• harder to see from the original why you cant ride over like the previous

• change B--m-->C to B<--s-->C

  • now it reads A--->B<--s-->C or

    C<--s-->B<---A

    • you can start at C, ride to B, but cannot ride from B to A because the arrow will not let you

you can go from All to Most to Some

you cant go from Some to Most to All

eh im not a big fan of the implicit example.

The one im using for my notes:

Although the restaurant was packed, some tables were empty.

@HaileyTran2116

I'm going to use "All birds can fly" to explain this, and let's just pretend there are 100 birds:

I think the confusion is that you're interpreting “some” as “some but not all” and "most" as "most but not all."

Logically, “some” only means “at least one.” So if 100 of the birds can fly (100%), that still satisfies “at least one can fly.” If you want to exclude 100 (100%), you would have to say “some but not all.”

• "Some but not all" would change the range to be 1-99 birds, and in that case you're right some could not equal 100%

Logically, "most" only means "more than half." So if 100 of the birds can fly (100%), that still satisfies "more than half can fly." If you want to exclude 100 (100%), you would have to say "most but not all."

• "Most but not all" would change the range to be 51-99 birds, and in that case you're right, most could not equal 100%

List with a couple added:

If and only if

If but only if

Then and only then

Then but only then

When and only when

When but only when

All but only

Or... but not both

If... then... but not otherwise

i dont think cannot is being used here as an indicator. to me it reads more "not jedi unless extraordinary discipline" so we negate not jedi and make sufficient to get J and everything after unless stays the same and becomes necessary to get D

so J---->D

INCLUSIVE OR-

1 premise might say:

"i will go to either the store or the pool today."

term 1: store = S

term 2: pool = P

at minimum i gotta go to at least one of these places, so if i dont go to one of them then i MUST go to the other

valid inference 1: /S--->P

valid inference 2: /P--->S

while its possible i could go to both we dont def know that just from the single premise, we'd need more context

thats why its invalid to say:

S----->/P

P---->/S

think about it...if i go to the store does that mean i def didnt go to the pool (and vise versa)? no because its totally possible i go to both today, we just dont know yet

EXCLUSIVE OR/OR, BUT NOT BOTH -

1 premise might say:

"I am either in New York or California."

term 1: New York = N

term 2: California = C

think about it...can i be in New York and California? using commonsense assumption (which you are allowed to use on the LSAT) you know theres literally no way to be in both states at the same time. if youre in one then you cant be in the other. and if youre not in one then you must be in the other

thats why its valid to say:

N--->/C

C---->/N

^(if im in one of the states, then i cant be in the other one)

and

/N---->C

/C---->N

^(if im not in one of the states, then i must be in the other one)

this premise would work exactly the same if it read:

I am either in New York or California, but not both.

how do you know if you can make a commonsense assumption?

if on the LSAT it said:

I am either in Vexoria or Xylvarra.

-you literally have no idea what these two places are or where they are. maybe they overlap in some way and you could possibly be in both at the same time. you would NOT be able to make a commonsense assumption that its impossible to be in both at the same time. it would have to say ".....,but not both." for you to know that.

the only valid inferences you'd be able to make are:

/V---->X

/X---->V

^(if im not in one of these places, i must be in the other place)

invalid inferences:

V---->/X

X---->/V

^(there is no way for you to know that being in one place means you def cant be in the other thats why these are invalid)

I don't like the idea of thinking about "unless, except, without, until" as both possibly sufficient and necessary indicators. So I label all of these as necessary condition indicators with a special rule:

• 1. Everything directly after "unless/except/without/until" becomes the necessary condition

• 2. The rest of the premise you negate it and it becomes the sufficient condition

Blackouts will occur unless the heat wave abates.

1. everything after unless = heat wave abates = necessary condition

2. the rest of the premise = blackouts will occur ---> negate this so it now reads blackouts wont occur = sufficient condition

/BO---->HWA

if holding the idea in your head that these indicators live in this separate group of possibly being both S and N indicators depending on which side you choose to negate is tripping you up, then always make everything directly after the "unless, etc." the necessary. Now you dont need a group 3:)

how i broke it down:

corn A and S = look same

corn A and corn b = look less same

step 1: corn A and S vs corn A and corn B

step 2: which one more closely related in looks?

step 3: corn A and S winner